Figure 3.

Neighbor-joining trees showing mosaic evolution within gene pairs. Neighbor-joining trees of gene pairs a) and d) BMP8A/B, b) and e) DDX19A/B and c) and f) TUBG1/2 were created in MEGA3 using a Tamura-Nei model of sequence evolution. Exons were divided into two categories and phylogenetic trees, showing a), b) and c) divergent evolution or d), e) and f) concerted evolution, are illustrated. Opossum Bmp8, chicken Ddx19 and chicken Tubg were used as outgroups to root the trees. Bootstrap values (10,000 replicates) are shown on the interior branches of the tree. A distance scale is shown below each tree. Underlined species in a) and d) are missing exon 1, preventing the use of this exon in the phylogenetic analysis. Additionally, maximum likelihood trees were created for comparison, showing highly similar patterns of evolution with the above trees [see Additional file 5].